Biological control of mosquito larvae of Culex quinquefasciatus Say using freshwater fish Carassius auratus Linn and Poecilia reticulata Peters

Abstract

Culex quinquefasciatus is the vector of Wuchereria bancrofti, avian malaria, and arboviruses. The Carassius auratus and Poecilia reticulata were evaluated against the larvae of C. quinquefasciatus and observed remarkable larval consumption. C. auratus and P. reticulata can be used against mosquitoes for integrated vector control management programme.

Keywords

Arboviruses, Insecticides, Larvae, Predators

Introduction

Biological control of vector mosquitoes is an important and effective means for controlling transmission of many dreadful mosquito-borne diseases such as, filariasis, malaria, JE, dengue fever, etc. Culex quinquefasciatus is the vector of Wuchereria bancrofti, avian malaria, and arboviruses. Recently researchers are focused to use biocontrol agents like fishes rather than chemical insecticides due to the adverse effects of chemical insecticides, widespread resistance in target insects, soaring price of chemical insecticides and other operational difficulties. Among the numerous predators, fish have been used since the early 1900’s to control vector mosquito larvae. Use of larvivorous fishes in the mosquito control is well documented.

Materials and Methods

The fishes of Carassius auratus and Poecilia reticulata ranging from 0.470 ± 05 mg and 0.475 ± 05 mg was used for feeding assay conducted by the method of NVBDCP [1]. After a period of seven days of acclimatization the experiment was conducted in laboratory conditions. Prestarved adult fish (n=1) was individually placed in 1 litre of dechlorinated water with fifty late third instar or early fourth instar larvae of Culex quinquefasciatus in a glass container. Five replicates were maintained at a time. No food was added in the jar as per WHO norms. Larval consumption rate was observed every three hours. Total larval consumption was recorded at the end of 24 hours.

Result and Discussion

All five fishes of C. auratus consumed 43, 44, 42, 40 and 43 larvae and 7, 6, 8, 10 and 7 larvae at the end of 3rd and 6th hours individually. However, the Poecilia reticulata fed 3, 6, 5, 5, 3 larvae in 3rd hr; 4, 7, 8, 15, 5 larvae in 6th hr, 7, 4, 6, 5 and 8 larvae in 9th hr individually 14, 5, 8, 7 and 8 larvae in 12th hour 12, 10, 10, 5 and 6 larvae in 15th hr; 4, 10, 8, 8 and 10 larvae in 18th hr and 6, 8, 5, 5 and10 larvae at the end 21st hr of introduction of fish (Table 1). Tilapia zilli, Oreochromis mossabicus, C. auratus, Aphanius dispar, Gambusia affinis and P. reticulata showed promising results against mosquitoes by WHO [2]. The P. reticulata each ate an average of 41.0 Culex sp. larvae/day, with females fed approximately twice as many as males [3]. The mean larval consumption rate of Aphanius dispar against Anopheles stephensi 128 ± 0.2 to 204 ± 6; Cx. quinquefasciatus 24 ± 4 to 58 ± 10; Aedes aegypti 43 ± 5 to 68 ±2 [4].

Table 1: Larval Consumption rate of Carassius auratus and Poecilia reticulata at 24 hr.

Conclusion

The feeding behavior of C. auratus was faster and fed all the 50 larvae at the end of 6 hour of introduction of fish, whereas P. reticulata fed slowly and fed all the 50 larvae at the end of 21st of introduction of fish individually. C. auratus and P. reticulata can be used against mosquitoes for integrated vector control management programme.

References

1. NVBDCP, Guidelines on the use of larvivorous fish for vector control.
2. World Health Organization. Report of the International Seminar on Integrated control of mosquito vectors, Adana, Turkey, 2- 14, WHO. Geneva, 1981; p. 59.
3. Elias M et al. Biological control of Mosquito larvae by Guppy fish.Bangaladesh Med. Res. Counc. Bull.1995; 21: 81-86.
4. Haq S and Yadav SR. Geographical distribution and evolution of Mosquito larvivorous potential of Aphaniusdispar (Ruppell), a native fish of Gujarat, India. J Vector Borne Dis. 2011; 48: 236-2 40.